This application claims the benefit of Korean Application No. 2002-68499, filed Nov. 6, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates, in general, to cooling apparatuses and, more particularly, to a cooling apparatus with two or more cooling chambers which are independently cooled.
2. Description of the Related Art
Generally, a cooling apparatus of an independent cooling type is partitioned into two cooling chambers, that is, a freezer compartment and a refrigerator compartment, by a partition wall. Two doors are hinged to a cabinet of the apparatus, each of which opens and closes a respective one of the cooling chambers. An evaporator and a fan are mounted to an inside surface of the freezer compartment to produce cool air and supply the cool air to the freezer compartment. Similarly, the refrigerator compartment is provided on an inside surface with an evaporator and a fan to produce cool air and supply the cool air to the refrigerator compartment. That is, cool air is independently supplied into both the freezer compartment and the refrigerator compartment. Such a cooling technique is referred to as an independent cooling technique.
FIG. 1 is a view illustrating a closed refrigeration circuit for a conventional cooling apparatus. As illustrated in FIG. 1, the refrigeration circuit of the conventional cooling apparatus includes a compressor 101, a condenser 102, a capillary tube 104, a refrigerator compartment evaporator 105, and a freezer compartment evaporator 107 which are connected to each other by refrigerant pipes to perform a refrigeration cycle. In the apparatus shown in FIG. 1, the capillary tube 104 serves to expand a refrigerant. The refrigeration circuit of the conventional cooling apparatus also includes a first motor 103a to drive a condenser fan 103, a second motor 106a to drive a refrigerator compartment fan 106, and a third motor 108a to drive a freezer compartment fan 108.
In such a conventional cooling apparatus, the freezer compartment is used for storing frozen foods. The known optimum temperature range of the freezer compartment is in a range including xe2x88x9218xc2x0 C. and xe2x88x9220xc2x0 C. Meanwhile, the refrigerator compartment is used for storing non-frozen foods for a lengthy period of time to maintain the freshness of the food. The known optimum temperature range of the refrigerator compartment is in a range including xe2x88x921xc2x0 C. and 6xc2x0 C.
As such, the optimum temperature range of the refrigerator compartment is different from that of the freezer compartment, but, in the conventional refrigerator, a refrigerant evaporating temperature of the refrigerator compartment evaporator 105 is equal to a refrigerant evaporating temperature of the freezer compartment evaporator 107. Thus, the temperature of the refrigerator compartment may be excessively and undesirably low. When the temperature of the refrigerator compartment is excessively low, an operating time of the refrigerator compartment fan 106 is appropriately controlled to prevent the refrigerator compartment from being overcooled. Since a pressure of the refrigerant in the capillary tube 104 is reduced according to the refrigerant evaporating temperature demanded by the freezer compartment evaporator 107, the above-mentioned problem arises. That is, when the extent of the pressure reduction is determined on the basis of the refrigerant evaporating temperature demanded by the freezer compartment evaporator 107, the refrigerant in the refrigerator compartment evaporator 105 evaporates at an excessively low temperature, so the temperature of the refrigerator compartment may fall below the optimum temperature. In this case, frost is formed on a surface of the refrigerator compartment evaporator 105, thus undesirably hindering the refrigerator compartment from maintaining a high percentage of humidity. Furthermore, the evaporating efficiency of the refrigerator compartment evaporator 105 becomes low, thus resulting in low cooling efficiency of the refrigerator. Since the refrigerant must be compressed in the compressor 101 considering the refrigerant evaporating temperature demanded by the freezer compartment evaporator 107, a load imposed on the compressor 101 is increased, so the energy efficiency ratio of the cooling apparatus is low.
Accordingly, it is an aspect of the present invention to provide a cooling apparatus which achieves various refrigeration cycles by controlling refrigerant paths, thus accomplishing optimum refrigerant evaporating temperatures demanded by a refrigerator compartment evaporator and a freezer compartment evaporator, and allowing either the refrigerator compartment or the freezer compartment to be independently cooled as desired, therefore increasing cooling efficiency and cooling speed of the cooling apparatus.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and/or other aspects of the present invention are achieved by providing a cooling apparatus, comprising a compressor to compress a refrigerant, first and second evaporators to evaporate the refrigerant compressed by the compressor, first, second, and third expansion units, and a path control unit. The first expansion unit is installed in series with an inlet of the first evaporator, and reduces a pressure of the refrigerant to expand the refrigerant prior to flowing into the first evaporator. The second and third expansion units are installed in series with an inlet of the second evaporator, and reduce a pressure of the refrigerant to expand the refrigerant prior to flowing into the second evaporator. The path control unit forms a first refrigerant path so that the refrigerant flowing from the first evaporator flows into either the second evaporator or the third expansion unit, forms a second refrigerant path so that the refrigerant flowing from the second expansion unit flows into the second evaporator, or forms a third refrigerant path so that the refrigerant flowing from the second expansion unit flows into the third expansion unit.